Anerood Jugnauth, 86, who has been in his post since 2014, the latest of several terms at the helm, announced on Saturday he would step down in favour of his son and Finance Minister Pravind Jugnauth, 55, citing the need for “a young leadership”.

President Ameenah Firdaus Gurib-Fakim, who holds a largely ceremonial role on the Indian Ocean Island, said Pravind Jugnauth had been issued with a letter of appointment as the new prime minister on Monday.

The formal swearing-in was due later in the day.

“Everywhere on the island it can be seen that the population is against the ‘father and son deal’ which has not gone through an election,” said Paul Berenger, a former prime minister and member of the opposition Mauritian Militant Movement.

“We challenge Pravind Jugnauth to organise a referendum on this deal. Otherwise, we need to call a general election,” Berenger said, speaking on Sunday after the prime minister announced his plan to step down for his son.

After opposition parties met on Monday, Berenger said opponents would demonstrate against the appointment.

Xavier-Luc Duval, the leader of the opposition coalition, said Anerood Jugnauth’s failure to resign as an member of parliament showed he would act as a “babysitter” for his son.

Anerood Jugnauth, who has presided over steady economic growth on the island that relies heavily on tourism and financial services, told the nation in a televised speech that he would stay on in government but in an unspecified new role.

In Mauritius, prime ministers can be appointed provided they have majority support in parliament, without a new election. The Militant Socialist Movement, the party of the Jugnauths, has a majority even after one party left the coalition in December.

Politics in Mauritius, a nation of just 1.3 million people, has long seen a few families dominating top posts in the decades since independence in 1968.

Navin Ramgoolam, who was prime minister in the late 1990s and from 2010 to 2014, was the son of the nation’s first premier after independence. But he secured the post after winning an election more than a decade after his father left office.